Electrode arrangements for tissue stimulation and methods of use and manufacture

ABSTRACT

A lead has a paddle body with a non-conductive material and multiple electrodes disposed within the non-conductive material. At least one of the electrodes includes one or more anchoring arrangement, such as opening(s) through the electrode through which the non-conductive material can pass; anchors that extend away from the electrode and into the non-conductive material of the paddle body; or flow-through anchors attached to the electrode with an opening through which the non-conductive material may pass.

FIELD

The present invention is directed to the area of devices and methods forstimulation of tissue using an array of electrodes, as well as methodsof making and using the devices. In addition, the present invention isdirected to the area of devices and methods for stimulation of tissueusing electrodes with an anchoring mechanism to retain the electrodeswithin a paddle body, as well as methods of making and using thedevices.

BACKGROUND

Stimulators have been developed to provide therapy for a variety ofdisorders, as well as for other treatments. For example, stimulators canbe used in neurological therapy by stimulating nerves or muscles, forurinary urge incontinence by stimulating nerve fibers proximal to thepudendal nerves of the pelvic floor, for erectile and other sexualdysfunctions by stimulating the cavernous nerve(s), for reduction ofpressure sores or venous stasis, etc.

As one example, spinal cord stimulation is a well accepted clinicalmethod for reducing pain in certain populations of patients. Stimulatorshave been developed to provide therapy for a variety of treatments. Forexample, stimulators can be used to stimulate nerves, such as the spinalcord, muscles, or other tissue. A stimulator can include a controlmodule (with a pulse generator), one or more leads, and an array ofstimulator electrodes on each lead. The stimulator electrodes are incontact with or near the nerves, muscles, or other tissue to bestimulated. The pulse generator in the control module generateselectrical pulses that are delivered by the electrodes to body tissue.As an example, electrical pulses can be provided to the dorsal columnfibers within the spinal cord to provide spinal cord stimulation.

BRIEF SUMMARY

One embodiment is a lead having a paddle body with a non-conductivematerial and multiple electrodes disposed within the non-conductivematerial. At least one of the electrodes includes a top portion, abottom portion, and a sidewall portion extending from the top portion tothe bottom portion. At least one of the electrodes defines at least oneopening through which the non-conductive material extends.

Another embodiment is a lead having a paddle body with a non-conductivematerial and multiple electrodes disposed within the non-conductivematerial. At least one of the electrodes includes one or more anchorsthat extend away from the electrode and into the non-conductive materialof the paddle body.

Yet another embodiment is a stimulation system that includes any of theleads described above and a control module coupleable to the lead forproviding electrical signals to the electrodes for stimulating tissue.

A further embodiment is a method of making a lead by providing aplurality of electrodes where at least one of the electrodes includes atop portion, a bottom portion, and a sidewall portion extending from thetop portion to the bottom portion. At least one of the electrodesdefines at least one opening. The plurality of electrodes is disposed ina non-conductive material so that the non-conductive material passesthrough the at least one opening.

Yet another embodiment is a method of making a lead by providingmultiple electrodes where at least one of the electrodes has one or moreanchors that extend away from the electrode. The electrodes are disposedin a non-conductive material so that the one or more anchors extend intothe non-conductive material.

BRIEF DESCRIPTION OF THE DRAWINGS

Non-limiting and non-exhaustive embodiments of the present invention aredescribed with reference to the following drawings. In the drawings,like reference numerals refer to like parts throughout the variousfigures unless otherwise specified.

For a better understanding of the present invention, reference will bemade to the following Detailed Description, which is to be read inassociation with the accompanying drawings, wherein:

FIG. 1 is a schematic illustration of one embodiment of a stimulationsystem, according to the invention;

FIG. 2 is a schematic perspective top view of one embodiment of a paddlebody, according to the invention;

FIG. 3 is a schematic perspective top view of one embodiment of anelectrode, according to the invention;

FIG. 4 is a schematic perspective bottom view of another embodiment ofan electrode, according to the invention;

FIG. 5 is a schematic block diagram of one embodiment of a stimulationsystem, according to the invention;

FIG. 6 is a schematic bottom view of a third embodiment of an electrode,according to the invention;

FIG. 7 is a schematic side view of the electrode of FIG. 6;

FIG. 8 is a schematic bottom view of a fourth embodiment of anelectrode, according to the invention; and

FIG. 9 is a schematic bottom view of a fifth embodiment of an electrode,according to the invention.

DETAILED DESCRIPTION

The present invention is directed to devices and methods for stimulationof tissue using an array of electrodes, as well as methods of making andusing the devices.

In addition, the present invention is directed to devices and methodsfor stimulation of tissue using electrodes with an anchoring mechanismto retain the electrodes within a paddle body, as well as methods ofmaking and using the devices.

FIG. 1 illustrates schematically one embodiment of a stimulation system100.

The stimulation system includes a control module (e.g., a stimulator orpulse generator) 102, a paddle body 104, and at least one lead body 106coupling the control module to the paddle body. The paddle body 104 andthe lead body 106 form a lead. The paddle body 104 typically includes anarray of electrodes 154. It will be understood that the system forstimulation can include more, fewer, or different components and canhave a variety of different configurations including thoseconfigurations disclosed in the stimulation system references citedherein. Examples of stimulation systems with electrode leads are foundin, for example, U.S. Pat. Nos. 6,181,969; 6,516,227; 6,609,029;6,609,032; and 6,741,892; and U.S. patent applications Ser. Nos.11/238,240; 11/319,291; 11/327,880; 11/375,638; 11/393,991; and11/396,309, all of which are incorporated by reference. The stimulationsystem or components of the stimulation system, including one or more ofthe lead body 106, the paddle body 104 and the control module 102, aretypically implanted into the body. The stimulation system can be usedfor a variety of applications including, but not limited to, brainstimulation, neural stimulation, spinal cord stimulation, and the like.

FIG. 2 illustrates a schematic top view of one embodiment of the paddlebody 104 which includes an array of electrodes 154 disposed in anon-conductive material 132. The electrodes 154 can be made using anyconductive material. Examples of suitable materials include metals,alloys, conductive polymers, conductive carbon, and the like, as well ascombinations thereof. The number of electrodes 154 in the array ofelectrodes 154 may vary. For example, there can be two, four, six,eight, ten, twelve, fourteen, sixteen, or more electrodes 154. As willbe recognized, other numbers of electrodes 154 may also be used.

A variety of different arrangements of the electrode(s) 154 can be used.For example, the electrodes 154 may be arranged in an array in two ormore parallel columns, as illustrated schematically in FIGS. 1 and 2.The columns of electrodes can be aligned or staggered from one another,or in any other desired column or row arrangement. The electrodes mayalso be arranged, for example, in a single column, or “in line,” alongthe longitudinal axis of a small diameter lead body. In otherembodiments, the electrodes may be placed circularly or elliptically orin any other suitable arrangement including any combination ofarrangements described herein. The arrangement of electrodes may besymmetrical or asymmetrical.

The non-conductive material 132 of the paddle body 104 can be made ofany non-conductive, biocompatible material including, for example,silicone, polyurethane, polyetheretherketone (PEEK), epoxy, and the likeor combinations thereof. The non-conductive material 132 may be formedin the desired shape by any process including, for example, molding(including injection molding), casting, and the like. Preferably, thenon-conductive material does not cover the top surface 156 (or at leasta substantial portion of the top surface 156) of the electrodes 154.

In one embodiment, the non-conductive material 132 is molded orotherwise formed around the electrodes 154. Examples of methods forforming the paddle body in this manner are described in U.S. patentapplication Ser. No. 11/319,291, incorporated herein by reference. Forexample, the non-conductive material 132 can be molded around theelectrodes in one or more steps. As one example, the electrodes 154 canbe positioned within a mold and the non-conductive material can bemolded around the electrodes leaving both the top and bottom surfaces ofthe electrodes exposed. Conductors (described below) can be attached tothe bottom surface of the electrodes and then additional non-conductivematerial can be molded over the bottom surface of the electrodes.

In at least some embodiments, the non-conductive material flows aroundthe electrodes during a molding process. The non-conductive materialthen becomes a solid mass to set the paddle shape. This process ofconversion to a solid mass may be a result of cooling the non-conductivematerial, for example, if the flowing material is a thermoplasticpolymer. In some embodiments, the non-conductive material that flowsduring the molding process is initially a monomeric material or anuncrosslinked polymeric material. The non-conductive material may thenbe formed into a solid mass by, for example, polymerizing the monomericmaterial or crosslinking the polymeric material (or any combinationthereof.)

Because the electrodes 154 and the non-conductive material 132 may bemade of dissimilar materials (e.g. metal and plastic) there may be sometendency for the materials to separate during or after manufacture.FIGS. 6 and 7 schematically illustrate a bottom view and a side view,respectively, of one embodiment of an electrode 154 with one or moreopenings 180. During manufacture, and in some instances even afterwards,the non-conductive material molded around the sides and bottom of theelectrode can extend through the openings 180. This can providestability for the electrode 154 within the paddle body 104.

The electrode 154 of the illustrated embodiment has a pot-like orbowl-like shape (see, e.g., FIG. 4) with a top portion 182 (the bottomsurface of which is seen in FIG. 6) with a sidewall portion 184extending to a bottom portion 186. This bottom portion 186 may beflanged, as illustrated in FIG. 6, to provide for stability within thenon-conductive material.

The openings 180 are typically formed in the sidewall portion 184 orbottom portion 186 (see FIG. 9) of the electrode 154. The electrode caninclude one or more openings 180. If the electrode 154 includes multipleopenings 180, these openings can be spaced in any arrangement includingsymmetrical and non-symmetrical arrangements. FIG. 6 illustratesopenings at the ends of the electrode, as well as along the longitudinalsides of the electrode. FIG. 8 illustrates another embodiment withopenings 180 only at ends of the electrode. FIG. 9 illustrates yetanother embodiment with openings positioned on the flange forming thebottom portion 186 of the electrode 154. It will be recognized that someembodiments may have openings in both the sidewall portion 184 andbottom portion 186.

The openings 180 can have any shape. In the illustrated embodiment, theopenings have a slot shape. The openings 180 are typically sufficientlywide and long to permit the non-conductive material to flow, orotherwise pass, through the openings. In one embodiment, the openingshave a width in the range of 0.001 to 0.01 inches (e.g., 0.025 to 0.25mm) and a length in the range of 0.01 to 0.1 inches (e.g., 0.25 to 2.5mm). In one embodiment, the non-conductive material flows through theopenings and then cools, or is polymerized or cross-linked, to form asolid mass that passes through the openings and facilitates stability ofthe electrode 154 in the paddle body 104.

There are other anchoring arrangements. FIGS. 3 and 4 schematicallyillustrate top and bottom views, respectively, of one embodiment of anelectrode 154 with one or more anchors 160. These anchors 160 extendinto the non-conductive material 132 to facilitate retention of theelectrode 154 within the non-conductive material 132. Generally, the topand bottom surfaces of the anchors are covered by the non-conductivematerial 132 when the electrodes is in place within the completed paddlebody 104. Accordingly, the position of the anchors on the electrode 154is selected with the understanding that the top surface 156 of theelectrode is typically exposed. In the illustrated embodiments of FIGS.3 and 4, the anchors 160 extend from, or near, a bottom surface 164 ofthe electrode 154. In an alternative embodiment, the anchors 160 canextend inwardly (for example, inward from the bottom surface of theelectrode) beneath the top surface of the electrode. There should bespace between the top surface and the anchor for the non-conductivematerial.

When more than one anchor 160 is used, the anchors can be disposed inany manner around the electrode 154. In one embodiment, at least twoanchors 160 are disposed on opposite sides of the electrode 154 asillustrated, for example, in FIGS. 3 and 4. There may be one or moreanchors on each opposite side. In other embodiments, anchors can extendfrom three or four sides of the electrode. Optionally, the anchors maybe offset laterally from each other, as illustrated, for example inFIGS. 3 and 4, to further facilitate retention.

The size and shape of the anchors 160, the length that the anchorsextend from the electrode 154, and the number and placement of anchors160 can vary and may be selected to provide a desired amount ofstability of the electrode within the paddle body 104. Length of theanchors may be restricted by the separation distance between adjacentelectrodes to avoid contact. By offsetting the anchors laterally (asillustrated, for example, in FIGS. 3 and 4) the anchors of adjacentelectrodes may be offset from each other to avoid contact while allowingcloser placement.

Optionally, the anchor 160 may include one or more openings 162 thatextends through the anchor. The non-conductive material 132 may passthrough the opening(s) 162 to further facilitate retention of theelectrode 154 within the non-conductive material 132. Moreover, if thenon-conductive material 132 is molded around the electrode 154, aportion of the non-conductive material may pass through the opening(s)162 during the molding process to provide further stability for theelectrode within the non-conductive material.

Yet another anchoring arrangement is illustrated in FIG. 4 as one ormore attached flow-through anchors 170. In the illustrated embodiment,the flow-through anchors are attached to a surface of the electrode (forexample, the bottom surface of the electrode as illustrated in FIG. 4)and include an opening 171 through which the non-conductive material maypass during the molding process. When set, the non-conductive materialthat extends through the opening can provide mechanical stability toretain the electrode within the non-conductive material. Theflow-through anchros may have a cylindrical shape, as illustrated inFIG. 4, or any other suitable shape with an opening through which thenon-conductive material may flow. The flow-through anchors can be madeof any material and attached to the electrode in any manner. In oneembodiment, the flow-through anchors are made of metal and attached bywelding or soldering the anchors to the electrode.

Turning again to FIG. 1, a conductor (not shown) is attached to each ofthe electrodes 154 and extends along the lead body 106 to the controlmodule 102 to conduct electrical pulses from the control module to theelectrode. Preferably, the conductor is attached to the back side of theelectrode 154, which is the side of the electrode 154 opposite the sidethat will be exposed to the body tissue.

The conductors can be made of any conductive material. Examples ofsuitable material for conductors include metals, alloys, conductivepolymers, conductive carbon, and the like, as well as combinationsthereof. In one embodiment, the conductors are insulated by aninsulating material except where the conductor makes contact with theelectrode 154. The insulating material may be any material that is apoor conductor of an electrical signal, including, for example, Teflon™,nylon, Mylar, other non-conductive polymers, and composite materials.The conductors may be attached to the electrodes by any methodincluding, for example, resistance welding, laser welding, conductiveepoxy, and the like. Preferably, the conductors are attached to theelectrodes 154 by a method that results in a durable attachment of theconductors to the electrodes 154 under expected usage conditions.

The lead body 106 is typically made of a non-conductive material suchas, for example, silicone, polyurethane, polyetheretherketone (PEEK),epoxy, and the like. Optionally, the lead body may include one or morelumens through which the conductors pass or through which a drug orother medication can pass to the site of stimulation near the electrodes154. The lead body 106 also may include a connector (not shown) forattachment to the control module 102 with contacts to connect theconductors to corresponding contacts of the control module.

The control module 102 typically includes a housing 114 with anelectronic subassembly 110 and, in at least some embodiments, a powersource 120 disposed within a chamber in the housing. Preferably, thehousing is resistant to moisture penetration into the chamber containingthe electronic subassembly and power source. In some embodiments, watermay diffuse through the housing. Preferably, the diffused water isrelatively pure, without substantial ionic content, as deionized wateris relatively non-conductive. The housing 114 may be made of anybiocompatible material including, for example, glass, ceramics, metals,and polymers, as well as combinations thereof. Preferably, the materialof the plastic housing is a hydrophobic polymer material. The housing114 may include additives such as, for example, fillers, plasticizers,antioxidants, colorants, and the like. The thickness of the walls of thehousing may also impact the moisture permeability of the housing. Aminimum thickness needed to achieve a particular degree of resistance tomoisture transport will often depend on the material selected for thehousing, as well as any additives.

Optionally, the housing 114 can be covered, in full or in part, with acoating. The coating can be provided to improve or alter one or moreproperties of the housing 114 including, for example, biocompatibility,hydrophobicity, moisture permeability, leaching of material into or outof the housing, and the like. In one embodiment, a coating can beapplied which contains a compound, such as, for example, a drug,prodrug, hormone, or other bioactive molecule, that can be released overtime when the control module is implanted. In another embodiment, thehousing itself may include such a compound to be released over timeafter implantation.

FIG. 5 is a schematic overview of one embodiment of components of asystem for stimulation, including an electronic subassembly 110 (whichmay or may not include the power source 120), according to theinvention. It will be understood that the system for stimulation and theelectronic subassembly 110 can include more, fewer, or differentcomponents and can have a variety of different configurations includingthose configurations disclosed in the stimulation system referencescited herein. Some or all of the components of the system forstimulation can be positioned on one or more circuit boards or similarcarriers within a housing of a control module, if desired.

Any power source 120 can be used including, for example, a battery suchas a primary battery or a rechargeable battery. Examples of other powersources include super capacitors, nuclear or atomic batteries,mechanical resonators, infrared collectors, thermally-powered energysources, flexural powered energy sources, bioenergy power sources, fuelcells, bioelectric cells, osmotic pressure pumps, and the like includingthe power sources described in U.S. Patent Application Publication No.2004/0059392, incorporated herein by reference.

As another alternative, power can be supplied by an external powersource through inductive coupling via the optional antenna 224 or asecondary antenna. The external power source can be in a device that ismounted on the skin of the user or in a unit that is provided near thecontrol module user on a permanent or periodic basis.

If the power source 120 is a rechargeable battery, the battery may berecharged using the optional antenna 224, if desired. Power can beprovided to the battery 120 for recharging by inductively coupling thebattery through the antenna to a recharging unit 210 external to theuser. Examples of such arrangements can be found in the stimulationsystem references identified above.

In one embodiment, electrical current is emitted by the electrodes 154to stimulate motor nerve fibers, muscle fibers, or other body tissues.The electronic subassembly 110 provides the electronics used to operatethe stimulation system and generate the electrical pulses at theelectrodes 154 to produce stimulation of the body tissues.

In the illustrated embodiment, a processor 204 is generally included inthe electronic subassembly 110 to control the timing and electricalcharacteristics of the stimulation system. For example, the processorcan, if desired, control one or more of the timing, frequency, strength,duration, and waveform of the pulses. In addition, the processor 204 canselect which electrodes can be used to provide stimulation, if desired.In some embodiments, the processor may select which electrode(s) arecathodes and which electrode(s) are anodes. In some embodiments withelectrodes disposed on two or more sides of the housing, the processormay be used to identify which electrodes provide the most usefulstimulation of the desired tissue. This process may be performed usingan external programming unit, as described below, that is incommunication with the processor 204.

Any processor can be used. For example, the processor can be as simpleas an electronic device that produces pulses at a regular interval orthe processor can be complex and capable of receiving and interpretinginstructions from an external programming unit 208 that allowmodification of pulse characteristics. In the illustrated embodiment,the processor 204 is coupled to a receiver 202 which, in turn, iscoupled to the optional antenna 224. This allows the processor toreceive instructions from an external source to direct the pulsecharacteristics and the selection of electrodes, if desired.

In one embodiment, the antenna 224 is capable of receiving signals(e.g., RF signals) from an external telemetry unit 206 which isprogrammed by a programming unit 208. The programming unit 208 can beexternal to, or part of, the telemetry unit 206. The telemetry unit 206can be a device that is worn on the skin of the user or can be carriedby the user and can have a form similar to a pager or cellular phone, ifdesired. As another alternative, the telemetry unit may not be worn orcarried by the user but may only be available at a home station or at aclinician's office. The programming unit 208 can be any unit that canprovide information to the telemetry unit for transmission to thestimulation system. The programming unit 208 can be part of thetelemetry unit 206 or can provide signals or information to thetelemetry unit via a wireless or wired connection. One example of asuitable programming unit is a computer operated by the user orclinician to send signals to the telemetry unit.

The signals sent to the processor 204 via the antenna 224 and receiver202 can be used to modify or otherwise direct the operation of thestimulation system. For example, the signals may be used to modify thepulses of the stimulation system such as modifying one or more of pulseduration, pulse frequency, pulse waveform, and pulse strength. Thesignals may also direct the stimulation system to cease operation or tostart operation or to start charging the battery. In other embodiments,the electronic subassembly 110 does not include an antenna 224 orreceiver 202 and the processor operates as programmed.

Optionally, the stimulation system may include a transmitter (not shown)coupled to the processor and antenna for transmitting signals back tothe telemetry unit 206 or another unit capable of receiving the signals.For example, the stimulation system may transmit signals indicatingwhether the stimulation system is operating properly or not orindicating when the battery needs to be charged. The processor may alsobe capable of transmitting information about the pulse characteristicsso that a user or clinician can determine or verify the characteristics.

The optional antenna 224 can have any form. In one embodiment, theantenna comprises a coiled wire that is wrapped at least partiallyaround the electronic subassembly within or on the housing.

Any method of manufacture of the components of the system forstimulation can be used.

The above specification, examples and data provide a description of themanufacture and use of the composition of the invention. Since manyembodiments of the invention can be made without departing from thespirit and scope of the invention, the invention also resides in theclaims hereinafter appended.

1. A lead comprising: a paddle body comprising a non-conductivematerial, and a plurality of electrodes disposed within thenon-conductive material, at least one of the electrodes comprising a topportion, a bottom portion, and a sidewall portion extending from the topportion to the bottom portion, at least one of the electrodes definingat least one opening through which the non-conductive material extends.2. The lead of claim 1, wherein the at least one opening comprises aplurality of openings.
 3. The lead of claim 1, wherein the at least oneopening has a slot shape.
 4. The lead of claim 1, wherein each of theelectrodes comprises a top portion, a bottom portion, and a sidewallportion extending from the top portion to the bottom portion, thesidewall portion defining at least one opening through which thenon-conductive material extends.
 5. A lead comprising: a paddle bodycomprising a non-conductive material, and a plurality of electrodesdisposed within the non-conductive material, at least one of theelectrodes comprising at least one anchor that extends away from theelectrode and into the non-conductive material of the paddle body. 6.The lead of claim 5, wherein the at least one anchor defines an openingthrough which the non-conductive material of the paddle body isdisposed.
 7. The lead of claim 5, wherein each of the plurality ofelectrodes comprises at least one anchor that extends into the leadbody.
 8. The lead of claim 5, wherein the at least one electrodecomprises a plurality of anchors that extend into the non-conductivematerial of the paddle body.
 9. The lead of claim 8, wherein theplurality of anchors comprises at least two anchors disposed on oppositesides of the at least one electrode.
 10. The lead of claim 9, whereinthe at least two anchors are laterally offset from each other.
 11. Thelead of claim 5, wherein the at least one anchor extends from, or near,a bottom surface of the electrode.
 12. A stimulation system, comprising:the lead of claim 1; and a control module coupleable to the lead forproviding electrical signals to the electrodes for stimulating tissue.13. The stimulation system of claim 12, wherein the lead and controlmodule are implantable.
 14. The stimulation system of claim 12, whereinthe control module comprises a power source.
 15. A method of making alead, comprising: providing a plurality of electrodes, wherein at leastone of the electrodes comprises a top portion, a bottom portion, and asidewall portion extending from the top portion to the bottom portion,at least one of the electrodes defining at least one opening; anddisposing the plurality of electrodes in a non-conductive material,wherein the non-conductive material passes through the at least oneopening.
 16. The method of claim 15, wherein disposing the plurality ofelectrodes in the non-conductive material comprises molding thenon-conductive material around the plurality of electrodes.
 17. Themethod of claim 15, wherein disposing the plurality of electrodes in anon-conductive material comprises flowing the non-conductive materialthrough the at least one opening and then forming a solid mass with thenon-conductive material.
 18. The method of claim 17, wherein forming asolid mass with the non-conductive material comprises polymerizing orcross-linking the non-conductive material.
 19. The method of claim 15,further comprising attaching a conductor to each of the plurality ofelectrodes.
 20. The method of claim 15, wherein molding thenon-conductive material comprises molding the non-conductive material toexpose at least a portion of a top surface of each of the plurality ofelectrodes.